It's certainly not in any way whatsoever similar to "prompting" a human. And yes there are definitely random processes involved. For an extremely objective prompt you may get very similar results but for general stuff like "write an e-mail about this or that" it will be significantly different each time.
Sure, but it's not like they're intentionally randomizing it. You can set parameters (like temperature or penalties), but it's not intentionally randomizing things.
